Three-Dimensional Shaping Method

ABSTRACT

A three-dimensional shaping method in which the powder supplying blade  2  is able to travel without any problems, in which a control system stores in advance a fine sintered region  11  so that any one of a cross-sectional area or a mean diameter in the horizontal direction, a shaping width and an undercut angle at the end is equal to or less than a predetermined extent, or the control system makes a determination in a sintering step, for said each element, so in the case of the raised sintered portions  12  forming on the upper side of the sintered region  11 , a rotating cutting tool  3  cuts the raised sintered portions  12  entirely or partially, thereby achieving the object.

FIELD OF THE INVENTION

The present invention relates to a three-dimensional shaping method inwhich lamination of a powder material and formation of a sintered layerbased on the thus laminated powder material are sequentially repeated,thereby producing a processed article.

DESCRIPTION OF THE RELATED ART

In the described three-dimensional shaping method, it is adopted torepeat a process of sintering for a position at which a processedarticle is expected to be formed by scanning with the use of an opticalbeam, after step of formation of the powder layer.

Although the three-dimensional shaping method is accompanied with thecharacteristics and advantages to the maximum extent in that varioustypes of shapes is adaptable in a processed article, it is unavoidableto often arise a case that a cross-sectional area in a horizontaldirection or a mean diameter is equal to or less than a predeterminedextent, a case that a shaping width is equal to or less than apredetermined extent, and a case that an undercut angle formed by anupper face and a lower inclined face at the edge is equal to or lessthan a predetermined extent.

In each of above-described cases, when a sintered region is irradiatedwith an optical beam, not only a previously expected sintered region isformed only on a powder layer which has already been formed, but also,as shown in FIG. 11(a), (b), it is unavoidable to often arise such acase that a raised sintered portion is formed at an upper side from aregion of the powder layer.

In the case that such raised sintered portion is formed, when a powdersupplying blade travels in order to form a powder layer on a next layeron the upper side of each layer to which sintering is performed, theraised sintered portion will, as shown in FIG. 11 (a), inevitably resultin an accident such that the raised sintered portion collides with thepowder supplying blade and a sintered region which has already beenprovided are deformed.

Furthermore, as shown in FIG. 11 (b), the powder supplying bladeinevitably collides and stops.

In order to avoid the above-described problem, inevitably, in a stagebefore traveling of the powder supplying blade for forming a powderlayer of the next step, it is necessary to cut the raised sinteredportion entirely or partially by using a rotating tool.

In order to cope with each of the cases that has been describedpreviously, a great amount of time and complicated know-how arenecessary for clearly distinguishing in advance a region at which theraised sintered portion is formed and also for realizing cutting of theraised sintered portion prior to a step of forming a next powder layer.

Nevertheless, spending a great amount of time does not always lead tofind out the raised sintered portion with certainty.

Furthermore, the know-how is based on accumulation of subjectiveexperience at work sites, and no objective standard can be obtained fromsuch know-how.

Taking account the above-described situation, it is impossible to findout conventional technologies for dealing with a raised sintered portionin dealing with possible formation of the raised sintered portion or theraised sintered portion which has already been formed.

For reference, Patent Document 1 explains a problem covering a raisedsintered portion on three-dimensional shaping and a method for dealingwith the problem (Paragraphs [0006], and [0045]). However, PatentDocument 1 recognizes the problem as a problem of degree of wettabilityin a stage that a powder layer is irradiated with an optical beam andalso dealt with the problem by using metal powder greater inwettability. Therefore, unlike the present invention, no considerationor measures are given to the raised sintered portion in each of thepreviously described cases.

In Patent Document 2, abnormal drive load with the use of a blade forkeeping uniform the surface of a powder layer or an optical method isemployed to detect a raised portion due to an abnormal sintered portion(Claim 3, Claim 4). Then, the raised portion due to an abnormal sinteredportion is removed, while repeating formation of a sintered layer orafter all the sintered layers are completely formed (the paragraph of[Solution] in [Abstract] and Claim 1).

However, where the drive load with use of the blade is employed todetect the raised portion due to an abnormal sintered portion, it isnecessary to stop the drive of the blade. On the other hand, it is alsoquite difficult to detect the abnormal sintered portion perfectly by anoptical method.

In Patent Document 3 as well, the abnormal protrusions are detectedbased on an increase in torque of a motor for driving a blade (Paragraph[0052] with regard to FIG. 6 and Claim 4) or detected by using anoptical method for checking the presence or absence of received light(Paragraphs [0061] to [0063] with regard to FIG. 15 and Claim 5).However, as with Patent Document 2, Patent Document 3 also hasunavoidable technological defects.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Published Unexamined Patent Application    No. 2004-277877-   Patent Document 2: Japanese Published Unexamined Patent Application    No. 2004-277881-   Patent Document 3: US Patent Publication No. 2006/0208396

DISCLOSURE OF THE INVENTION Problem(s) to be Solved by the Invention

An object of the present invention is to provide a configuration of athree-dimensional shaping method in which there is detected efficientlyand reliably a raised sintered part that will develop typically from afine sintered region in such a case that any one of a horizontal crosssection or a mean diameter, a shaping width and an undercut anglebetween an upper face and a lower inclined face at the edge, of asintered portion on each layer, is equal to or less than a predeterminedextent, thus enabling a powder supplying blade to travel around a nextlayer positioned on the upper side of the layer concerned without anyproblems.

Means for Solving the Problems

In order to solve the above problems,

regarding the case that a cross-sectional area or a mean diameter of asintered site in a horizontal direction is equal to or less than apredetermined extent, basic configurations of the present invention arecomposed of

(1)-1 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by an optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, comprising that acontrol system stores in advance a region at coordinate positions in ahorizontal direction and a height direction in which a cross-sectionalarea or a mean diameter of an expected sintered part in a horizontaldirection is equal to or less than a predetermined extent, and when theregion at the coordinate positions is present on an individual layer tobe sintered, the control system temporarily stocks the region at thecoordinate positions, and also after sintering of the layer concerned iscompleted, at an intermediate height position between the position ofthe surface on which the sintering has been completed and the lowestposition of a powder supplying blade moving in the horizontal directionfor forming a powder layer on a next layer on the upper side of thelayer concerned, a rotating cutting tool travels around the region atthe coordinate position in the horizontal direction and an outerperipheral vicinity thereof according to instructions of the controlsystem, thereby, in the case of a raised sintered portion forming on theupper side of the region at the coordinate position, the rotatingcutting tool cuts the raised sintered portion entirely or partially, and(1)-2 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by an optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, and comprisingthat on an individual layer to be sintered, a control system determinesa length of a shaping path formed by a continuous line for each scanningof the layer concerned by the optical beam and when the length isdetermined to be equal to or less than a predetermined extent, thecontrol system temporarily stocks coordinate positions in a horizontaldirection and a height direction at a region of the shaping path, whoselength has been determined to be equal to or less than the predeterminedextent, and also after sintering of the layer concerned is completed, atan intermediate height position between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade moving in the horizontal direction for forming apowder layer on a next layer on the upper side of the layer concerned, arotating cutting tool travels around the region at the coordinateposition in the horizontal direction and an outer peripheral vicinitythereof according to instructions of the control system, thereby, in thecase of a raised sintered portion forming on the upper side of theregion at the coordinate position, the rotating cutting tool cuts theraised sintered portion entirely or partially,

regarding the case that the shaping width of the sintered site is equalto or less than a predetermined extent, basic configurations of thepresent invention are composed of

(2)-1 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by an optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, comprising that acontrol system stores in advance a region at coordinate positions in ahorizontal direction and a height direction in which a horizontal widthof an expected sintered part is equal to or less than a predeterminedextent, and when the region at the coordinate positions is present on anindividual layer to be sintered, the control system temporarily stocksthe region at the coordinate positions, and also after sintering of thelayer concerned is completed, at an intermediate height position betweenthe position of the surface on which the sintering has been completedand the lowest position of a powder supplying blade moving in thehorizontal direction for forming a powder layer on a next layer on theupper side of the layer concerned, a rotating cutting tool travelsaround the region at the coordinate position in the horizontal directionand an outer peripheral vicinity thereof according to instructions ofthe control system, thereby, in the case of a raised sintered portionforming on the upper side of the region at the coordinate position, therotating cutting tool cuts the raised sintered portion entirely orpartially,(2)-2 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by an optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, comprising that onan individual layer to be sintered, a control system determines thenumber of parallel lines formed by folding back a continuous line foreach scanning of the layer concerned by the optical beam, and when thenumber of the lines is determined to be equal to or less than apredetermined number of the lines, the control system temporarily stockscoordinate positions in a horizontal direction and a height direction ata region of a shaping path in which the number of the lines isdetermined to be equal to or less than a predetermined amount of lines,and also after sintering of the layer concerned is completed, at anintermediate height position between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade moving in a horizontal direction for forming apowder layer on a next layer on the upper side of the layer concerned, arotating cutting tool travels around the region at the coordinateposition in the horizontal direction and an outer peripheral vicinitythereof according to instructions of the control system, thereby, in thecase of a raised sintered portion forming on the upper side of theregion at the coordinate position, the rotating cutting tool cuts theraised sintered portion is cut entirely or partially,

regarding the case that an undercut angle formed between an upper faceand a lower inclined face at the end is equal to or less than apredetermined extent,

basic configurations of the present invention are composed of

(3)-1 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by an optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, comprising that acontrol system stores in advance a region at coordinate positions in ahorizontal direction and a height direction in which the undercut angleformed between the upper face and the lower inclined face at the edge ofan expected sintered part is equal to or less than a predeterminedextent, and when the region at the coordinate positions is present on anindividual layer to be sintered, the control system temporarily stocksthe region at the coordinate positions, and also after sintering of thelayer concerned is completed, at an intermediate height position betweenthe position of the surface on which the sintering concerned has beencompleted and the lowest position of a powder supplying blade moving inthe horizontal direction for forming a powder layer on a next layer onthe upper side of the layer concerned, a rotating cutting tool travelsaround the region at the coordinate position in the horizontal directionand an outer peripheral vicinity thereof according to instructions ofthe control system, thereby, in the case that a raised sintered portionis formed which is positioned on the upper side of the region at thecoordinate position, the rotating cutting tool cuts the raised sinteredportion entirely or partially, and(3)-2 a three-dimensional shaping method in which after formation of apowder layer with a predetermined thickness, a step for sintering thepowder layer by the optical beam is performed at a predetermined numberof times and, thereafter, a periphery thereof is cut, comprising that onan individual layer to be sintered, a scanning position at the end of ascanning site of an optical beam is increased horizontally in region andin a state of projecting to a greater extent than a scanning position atthe edge of the optical beam on an immediately preceding sintered layerpositioned so as to be adjacent to a lower side of the layer concernedat a position lower than the scanning position concerned, and also aheight width between both ends thereof is divided by a horizontal widthto calculate a ratio, and when the ratio is determined to be equal to orless than a predetermined number, a control system temporarily stockscoordinate positions in a horizontal direction and a height direction atthe projection end in which the ratio is determined to be equal to orless than the predetermined extent and in a vicinity region thereof, andalso after sintering of the layer concerned is completed, at anintermediate height position between the position of the surface onwhich the sintering concerned has been completed and the lowest positionof a powder supplying blade moving in the horizontal direction forforming a powder layer on a next layer on the upper side of the layerconcerned, a rotating cutting tool travels around the region at thecoordinate position in the horizontal direction and an outer peripheralvicinity thereof according to instructions of the control system,thereby, in the case of a raised sintered portion forming on the upperside of the region at the coordinate position, the rotating cutting toolcuts the raised sintered portion entirely or partially.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view to explain for leading out a general formula inExample 1.

FIG. 2 is a plan view to explain for leading out a general formuladerived in Example 2.

FIG. 3 is a perpendicular sectional view to explain a numerical value ofa ratio in Example 3.

FIG. 4 shows a flowchart of forming each sintered layer of the basicconfiguration (1)-1.

FIG. 5 shows a flowchart of forming each sintered layer of the basicconfiguration (1)-2.

FIG. 6 shows a flowchart of forming each sintered layer of the basicconfiguration (2)-1.

FIG. 7 shows a flowchart of forming each sintered layer of the basicconfiguration (2)-2.

FIG. 8 shows a flowchart of forming each sintered layer of the basicconfiguration (3)-1.

FIG. 9 shows a flowchart of forming each sintered layer of the basicconfiguration (3)-2.

FIG. 10 is a side view which shows effects of the present invention inaccordance with the basic configurations (1)-1 and (1)-2.

FIG. 11 is a side view which explains problems of a raised sinteredportion in conventional technologies, and (a) shows a case that across-sectional area or a mean diameter in the horizontal direction isequal to or less than a predetermined extent, while (b) shows a casethat an undercut angle between an upper face and a lower inclined faceat the end is equal to or less than a predetermined extent.

DESCRIPTION OF THE SYMBOLS

-   1: Shaped article-   11: Sintered region-   12: Raised sintered portion-   2: Powder supplying blade-   3: Tool-   4: Powder layer

MODE FOR CARRYING OUT THE INVENTION

Each of the basic configurations (1)-1 and (1)-2 is a method for dealingwith the formation of a raised sintered portion 12 resulting from thefact that a cross-sectional area or a mean diameter of a sintered partin the horizontal direction is equal to or less than a predeterminedextent. Each of the basic configurations (2)-1 and (2)-2 is a method fordealing with the formation of the raised sintered portion 12 resultingfrom the fact that a shaping width of the sintered part is equal to orless than a predetermined extent. Each of the basic configurations (3)-1and (3)-2 is a method for dealing with the formation of the raisedsintered portion 12 resulting from the fact that an undercut angleformed between an upper face and a lower inclined face at the end of thesintered part is equal to or less than a predetermined extent.

Of the above-described respective methods, each of the basicconfigurations (1)-1, (2)-1 and (3)-1 stands on that the control systemstores in advance the region at coordinate positions in the horizontaldirection and the height direction so that a value described in each ofthe above-described cases is equal to or less than a predeterminedextent, and when a raised sintered portion 12 is formed on the upperside of a sintered region 11, a rotating cutting tool 3 cuts the raisedsintered portion 12 entirely or partially according to control based onthe storage. On the other hand, each of the basic configurations (1)-2,(2)-2 and (3)-2 stands on that the control system determines whether ornot a value described in each of the above-described cases is equal toor less than a predetermined extent, and when the raised sinteredportion 12 is formed on the upper side of the sintered region 11, therotating cutting tool 3 cuts the raised sintered portion 12 entirely orpartially according to control based on the determination.

In the basic configuration (1)-1, the control system stores in advancethe region at the coordinate positions in the horizontal direction andthe height direction in which the cross-sectional area or the meandiameter of the expected sintered part in the horizontal direction isequal to or less than a predetermined extent.

Precisely, the basic configuration (1)-1 stands on that in the case ofthe raised sintered portion 12 forming on the upper side of the sinteredregion 11, the sintered portion 12 is cut entirely or partially by aprocess for each layer described in the flowchart shown in FIG. 4 on thebasis of the above-described storing.

Explaining in detail, when each layer is sintered, the region at thecoordinate positions in the horizontal direction and the heightdirection which has been stored by the control system is present on thelayer concerned, the control system temporarily stocks the region at thecoordinate positions, and also after sintering of the layer concerned iscompleted, at an intermediate height position between the position ofthe surface on which the sintering has been completed and the lowestposition of a powder supplying blade 2 moving in the horizontaldirection for forming a powder layer 4 on a next layer on the upper sideof the layer concerned, the rotating cutting tool 3 travels around theregion at the coordinate position in the horizontal direction and anouter peripheral vicinity thereof on the basis of instructions of thecontrol system, thereby, in the case of the raised sintered portion 12forming on the upper side of the region at the coordinate position, therotating cutting tool 3 cuts the sintered portion 12 entirely orpartially.

However, determination on whether or not the region concernedcorresponds to a region at the coordinate positions in which thecross-sectional area or the mean diameter in the horizontal direction isequal to or less than a predetermined extent and instructions for therotating cutting tool 3 on the basis of the determination are allcarried out according to an unit of sintered section on each sinteredlayer.

Usually, π mm² is set as a baseline of the cross-sectional area which isequal to or less than a predetermined extent. In most cases, 2 mm is setas a baseline of the mean diameter which is equal to or less than apredetermined extent.

In the basic configuration (1)-2, on sintering each layer, the controlsystem determines whether or not the length of a shaping path formed bya continuous line for each scanning by an optical beam on the layerconcerned is equal to or less than a predetermined extent.

The above-described determination is based on an empirical rule that adiameter of an optical beam and a line width on scanning are fixed foreach scanning by the optical beam and, therefore, the length of theshaping path determines a cross-sectional area or a mean diameter in thehorizontal direction.

The method for the basic configuration (1)-2 based on theabove-described determination stands on that in the case of the raisedsintered portion 12 forming on the upper side of the sintered region 11,the sintered portion is cut entirely or partially by a process for eachlayer described in the flowchart of FIG. 5.

Explaining in detail, when the above-described length is determined tobe equal to or less than a predetermined extent, the control systemtemporarily stocks the coordinate positions in the horizontal directionand the height direction at the region of the shaping path in which thelength is determined to be equal to or less than the predeterminedextent, and also after sintering of the layer concerned is completed, atan intermediate height position between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade 2 moving in the horizontal direction for forminga powder layer 4 on a next layer positioned on the upper side the layerconcerned, the rotating cutting tool 3 travels around the region of thecoordinate position in the horizontal direction and an outer peripheralvicinity thereof on the basis of instructions of the control system,thereby, in the case of the raised sintered portion 12 forming on theupper side of the region of the coordinate position, the rotatingcutting tool 3 cuts the raised sintered portion 12 entirely orpartially.

However, the determination on whether or not the length of the shapingpath is equal to or less than a predetermined extent and instructionsfor a rotating and cutting tool 3 based on the determination are allcarried out according to an unit of sintered section on each sinteredlayer.

It is noted that an example of specifically setting the length of theshaping path is as will be described later in Example 1.

In the basic configuration (2)-1, the control system stores in advancethe region at the coordinate positions in the horizontal direction andthe height direction in which the shaping width of an expected sinteredpart is equal to or less than a predetermined extent.

Precisely, the basic configuration (2)-1 stands on that in the case ofthe raised sintered portion 12 forming on the upper side of the sinteredregion 11, the sintered portion 12 is cut entirely or partially by theprocess for each layer described in the flowchart of FIG. 6 on the basisof the above-described storage.

Explaining in detail, the region at coordinate positions in a horizontaldirection and a height direction stored by the control system exists inthe layer concerned on sintering, the control system temporarily stocksthe region at the coordinate positions, and also after sintering of thelayer concerned is completed, at an intermediate height position betweenthe position of the surface on which the sintering has been completedand the lowest position of a powder supplying blade 2 moving in thehorizontal direction for forming a powder layer 4 on a next layer on theupper side of the layer concerned, the rotating cutting tool 3 travelsaround the region of the coordinate position in the horizontal directionand an outer peripheral vicinity thereof on the basis of instructions ofthe control system, thereby, in the case of the raised sintered portion12 forming on the upper side of the region at the coordinate position,the rotating cutting tool 3 cuts the raised sintered portion 12 entirelyor partially.

However, determination on whether or not the region concernedcorresponds to the region at the coordinate position in which a cuttingwidth is equal to or less than a predetermined extent and instructionsfor the rotating cutting tool 3 on the basis of the determination areall carried out according to an unit of sintered section on eachsintered layer.

In most cases, 2 mm is usually set as a baseline of the shaping widthwhich is equal to or less than a predetermined extent.

In the basic configuration (2)-2, on sintering each layer, the controlsystem determines the number of parallel lines formed by folding back acontinuous line for each scanning by an optical beam on the layerconcerned and determines that the number is equal to or less than apredetermined number. The above-described determination is based on anempirical rule that a diameter of an optical beam and a line width foreach scanning on an individual layer are fixed and, therefore, theshaping width is inevitably determined by the number of the lines.

The basic configuration (2)-2 based on the above-described determinationstands on that in the case of the raised sintered portion 12 forming onthe upper side of the sintered region 11, the raised sintered portion 12is cut entirely or partially by the process for each layer which isdescribed in the flowchart of FIG. 7.

Explaining in detail, when the above-described number is determined tobe equal to or less than a predetermined number, the control systemtemporarily stocks coordinate positions in a horizontal direction and aheight direction at the region of the shaping path in which the numberis determined to be equal to or less than the predetermined extent, andalso after sintering of the layer concerned is completed, at anintermediate height position between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade 2 moving in the horizontal direction for forminga powder layer 4 on a next layer positioned on the upper side of thelayer concerned, the rotating cutting tool 3 travels around the regionat the coordinate position in the horizontal direction and an outerperipheral vicinity thereof on the basis of instructions of the controlsystem, thereby, in the case where a raised sintered portion 12 formingon the upper side of the region at the coordinate position, the rotatingcutting tool 3 cuts the sintered portion 12 entirely or partially.

However, determination on whether or not the number is equal to or lessthan a predetermined number and instructions for the rotating cuttingtool 3 on the basis of the determination are all carried out accordingto an unit of sintered section on each sintered layer.

It is noted that an example of specifically setting the number of thelines is as will be described later in Example 2.

In the basic configuration (3)-1, the control system stores in advance aregion at coordinate positions in which an undercut angle formed betweenan upper face and a lower inclined face at the end of the sintered partis equal to or less than a predetermined extent.

Precisely, the basic configuration (3)-1 stands on that in the case ofthe raised sintered portion 12 forming on the upper side of the sinteredregion 11, the sintered portion 12 is cut entirely or partially by theprocess for each layer described in the flowchart of FIG. 8 on the basisof the above-described storing.

Explaining in detail, the region at coordinate positions in thehorizontal direction and the height direction, after sintering of thelayer concerned is completed, at an intermediate height position betweenthe position of the surface on which the sintering has been completedand the lowest position of a powder supplying blade 2 moving in thehorizontal direction for forming a powder layer 4 on a next layerpositioned on the upper side of the layer concerned, the rotatingcutting tool 3 travels around the region at the coordinate position inthe horizontal direction and an outer peripheral vicinity thereof on thebasis of instructions of the control system, thereby, in the case of araised sintered portion 12 forming on the upper side of the region atthe coordinate position, the rotating cutting tool 3 cuts the raisedsintered portion 12 entirely or partially.

It is noted that determination on whether or not the region concernedcorresponds to the region at the coordinate positions in which theundercut angle is equal to or less than a predetermined extent andinstructions for the rotating cutting tool 3 on the basis of thisdetermination are all carried out according to an unit of sinteredsection on each sintered layer.

Furthermore, inmost cases, 45 degrees is set as a baseline of theundercut angle which is equal to or less than a predetermined extent.

In the basic configuration (3)-2, on an individual layer to be sintered,a scanning position at the edge of a scanning site of an optical beam isincreased horizontally in region and in a state of projecting to agreater extent than a scanning position at the edge of the optical beamon an immediately preceding sintered layer positioned so as to beadjacent to a lower side of the layer concerned at a position lower thanthe scanning position concerned, and also a height width between bothends thereof is divided by a horizontal width to calculate a ratio, andwhether or not the ratio is equal to or less than a predetermined numberis used as a base for determination. This is based on an empirical rulethat where the ratio is equal to or less than a predetermined number,the undercut angle is also equal to or less than a predetermined extent.

However, both cases are adopted corresponding one case that a scanningdirection at the edge of an optical beam on each layer and a scanningdirection at the end of the optical beam on a next layer positioned onthe upper side of the layer concerned are in the same direction and theother case that they are in the opposite direction from each other.

With the above-described both cases taken into account, the method forthe basic configuration (3)-2 stands on that in the case of the raisedsintered portion 12 forming on the upper side of the sintered region 11,the sintered portion 12 is cut entirely or partially by the process foreach layer described in the flowchart of FIG. 9.

Explaining in detail, on an individual layer to be sintered, a scanningposition at the edge of a scanning site of an optical beam is increasedhorizontally in region and in a state of projecting to a greater extentthan a scanning position at the end of the optical beam on animmediately preceding sintered layer positioned so as to be adjacent toa lower side of the layer concerned at a position lower than thescanning position concerned, and also a height width between both endsis divided by a horizontal width to calculate a ratio, and when theratio is determined to be equal to or less than a predetermined number,the control system temporarily stocks the coordinate positions in thehorizontal direction and the height direction at the projection end inwhich the ratio is determined to be equal to or less than thepredetermined extent and an adjacent region thereof, and also aftersintering of the layer concerned is completed, at an intermediate heightposition between the position of the surface on which the sintering hasbeen completed and the lowest position of a powder supplying blade 2moving in the horizontal direction for forming a powder layer 4 on anext layer on the upper side of the layer concerned, the rotatingcutting tool 3 travels around the region at the coordinate position inthe horizontal direction and an outer peripheral vicinity thereof on thebasis of instructions of the control system, thereby, in the case wherea raised sintered portion 12 is formed which is positioned on the upperside of the region at the coordinate position in the horizontaldirection, cutting the sintered portion entirely or partially.

However, the height width and the horizontal width are different inbaseline of setting method, depending on the scanning direction of theoptical beam.

Precisely, upon setting the height width and the horizontal widthbetween both ends, where the scanning direction of the optical beam ateach end and in the vicinity thereof is along the direction at the endconcerned, the coordinate position on traveling at the end concerned isgiven as a baseline, and where the scanning direction of the opticalbeam at each end and in the vicinity thereof is not along the directionat the end concerned, the coordinate position at the end of afolding-back region at the end of the optical beam is given as abaseline.

However, determination on whether the ratio is equal to or less than apredetermined number or not and instructions for the rotating cuttingtool 3 on the basis of the determination are all carried out accordingto an unit of sintered section on each sintered layer.

It is noted that an example of specifically setting the ratio is asdescribed later in Example 3.

In the present invention based on each of the basic configurations, eventhough the raised sintered portion 12 has been formed, as shown in FIG.10, in a stage before the formation of a next layer positioned on theupper side of the layer concerned, the cutting tool 3 is rotated to cutthe raised sintered portion 12 entirely or partially, thus it ispossible to avoid collision between the powder supplying blade 2 and theraised sintered portion 12 on a next layer positioned on the upper sideof the layer concerned. It is therefore possible to achieve thethree-dimensional shaping in an extremely efficient manner.

It is noted that FIG. 10 shows the basic configuration (1)-1 and thebasic configuration (1)-2, but the above-described collision can also beavoided in the cases of basic configuration (2)-1, the basicconfiguration (2)-2, the basic configuration (3)-1 and the basicconfiguration (3)-2.

Hereinafter, a description will be given with reference to examples.

EXAMPLES Example 1

In the basic configuration (1)-2, when the diameter of an optical beamin the vicinity of the coordinate region is given as dram, the widthbetween scanning lines associated with folding-back of the optical beamis given as w mm, and the number of parallel traveling lines associatedwith folding-back of the optical beam is given as N, Example 1 ischaracterized in that the length of the shaping path formed for each ofthe optical beams is expressed by the formula shown below.

N{π(1−d ²/4)−(N−1)wd}/{(N−1)w+d} mm  [Formula 1]

The reason for the length of the shaping path expressed by the formulashown below is as follows:

N{π(1−d ²/4)−(N−1)wd}/{(N−1)w+d} mm  [Formula 2]

As shown in FIG. 1, in the case that a mean length of the N linestraveling in parallel is L mm, a width of the region surrounded by lineson both sides along the direction orthogonal to the parallel directionis expressed as (N−1)w.

As shown in FIG. 1, each of the (N−1) folding-back regions projects onlyby a radius of an optical beam of d/2 in the line direction at both endsof each of the N lines.

So, an area of the region which is surrounded by the N lines and alsoincludes the above-described projection regions is expressed as(N−1)w(L+d) mm.

A region projects only by the radius of an optical beam of d/2 in theorthogonal direction also in each of two outside lines in the N lines. Atotal area of these projecting regions is approximately Ld mm.

Furthermore, at both ends of each of the two outside lines, as shown inFIG. 1, four regions exist with the state surrounded by a quartercircular arc. A total area of the four regions is expressed as π d²/4mm.

Therefore, as described in the basic configuration (1)-1, where π mm² isset as an ordinarily adopted baseline in which a cross-sectional area inthe horizontal direction is equal to or less than a predeterminedextent, the formula shown below is established.

(N−1)w(L+d)+Ld+πd ²/4=π  [Formula 3]

And, the formula shown below can be led out.

L={π(1−d ²/4)−(N−1)wd}/{(N−1)w+d} mm  [Formula 4]

Therefore, when an entire length of the line in which the mean width ofthe N lines is given as L mm is given as L″, the formula shown below canbe obtained.

L′=NL=N{π(1−d ²/4)−(N−1)wd}/{(N−1)w+d} mm  [Formula 5]

Example 2

In the basic configuration (2)-2, Example 2 is characterized in thatwhere a diameter of an optical beam is given as d mm and a width betweenscanning lines associated with the folded-back optical beam is given asw mm, the number of the lines in the sintered region 11 is a maximumvalue of integer in terms of a numerical value of 1+(2−d)/w.

The reason for the formula shown below established as the shaping widthcan be explained as follows with reference to FIG. 2.

1+(2−d)/w  [Formula 6]

As apparent from FIG. 2, a width of the sintered region 11 formed by Ntraveling lines of parallel optical beams is expressed as (N−1)w+d.

Therefore, as described in the basic configuration (2)-1, where 2 mm isset as an ordinarily adopted baseline in which the shaping width isequal to or less than a predetermined extent, the formula shown below isestablished,

(N−1)w+d=2  [Formula 7]

and the formula shown below can be obtained.

N=1+(2−d)/w  [Formula 8]

Example 3

In the basic configuration (3)-2, Example 3 is characterized in that aratio which is obtained by dividing a height width between both ends bya horizontal width is 1:1.

The grounds thereof are demonstrated by the fact that, as shown in FIG.3, the undercut angle forms 45 degrees when the ratio is 1:1.

Effect of the Invention

In the present invention which is composed of the basic configurations(1)-1, -2, (2)-1, -2 and (3)-1, -2, a cause for forming a raisedsintered portion on each layer is detected in advance efficiently andreliably, and the sintered portion is cut entirely or partially by arotating cutting tool in a stage before the formation of a next layerpositioned on the upper side of the layer concerned. Thereby, it ispossible to prevent in advance problems in forming a powder layer on anext layer positioned on the upper side of the layer concerned.

The three-dimensional shaping method of the present invention is able toprovide efficient shaping without any problems in traveling of a powdersupplying blade, even if a raised sintered portion is formed bysintering a fine sintered region in such a manner that any one of across-sectional area or a mean diameter in the horizontal direction, ashaping width and an undercut angle at the edge is made equal to or lessthan a predetermined extent. Therefore, the method has a great range ofapplications.

1-13. (canceled)
 14. A three-dimensional shaping method comprising thesteps of: after formation of a powder layer with a predeterminedthickness, sintering the powder layer by an optical beam and repeatingthe formation and the sintering a predetermined number of times and,wherein the sintering and formation includes the following steps as toeach layer: on an individual layer to be sintered, for detecting alikelihood that raised sintered portions will be present after sinteringfrom a fine sintered region, determining by a control system a region atcoordinate positions in a horizontal direction and a height directionhaving one of a cross-sectional area and a mean diameter beforesintering the region, and when the one of the cross-sectional area andmean diameter is greater than a predetermined extent, the region issintered, when the one of the cross-sectional area and mean diameter isdetermined to be equal to or less than the predetermined extent,temporarily stocking coordinate positions in a horizontal direction anda height direction at a region of the shaping path by the controlsystem, whose one of the cross-sectional area and mean diameter has beendetermined to be equal to or less than the predetermined extent,sintering the divided block after temporarily stocking, causing therotating cutting tool to travel around the region at the temporarilystocked coordinate positions instructed by the control system in thehorizontal direction, after sintering of the layer concerned iscompleted, at an intermediate height position according to thetemporarily stocked coordinate positions instructed by the controlsystem in the height direction between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade moving in the horizontal direction for forming apowder layer on a next layer on the upper side of the layer concerned,so that the rotating cutting tool cuts any raised sintered portions, andcutting a periphery thereof according to a cutting tool traveling alongan outside edge of the periphery to form the layer of an article, thestep of cutting a periphery occurring according to one of the following:if the step of causing occurs, before or after the step of causing, orif the step of causing does not occur.
 15. The three-dimensional shapingmethod according to claim 14, wherein one of: the cross-sectional areais π mm² and the mean diameter is 2 mm.
 16. A three-dimensional shapingmethod comprising the steps of: after formation of a powder layer with apredetermined thickness, sintering the powder layer by an optical beamand repeating the formation and the sintering a predetermined number oftimes and, wherein the sintering and formation includes the followingsteps as to each layer: on an individual layer to be sintered, fordetecting a likelihood that raised sintered portions will be presentafter sintering from a fine sintered region, determining by a controlsystem a horizontal width of an expected sintered part before sinteringthe region, and when the horizontal width of the expected sintered partis greater than a predetermined extent, the region is sintered, when thehorizontal width of the expected sintered part is determined to be equalto or less than the predetermined extent, temporarily stockingcoordinate positions in a horizontal direction and a height direction ata region of the shaping path by the control system, whose horizontalwidth of the expected sintered part has been determined to be equal toor less than the predetermined extent, sintering the divided block aftertemporarily stocking, causing the rotating cutting tool to travel aroundthe region at the temporarily stocked coordinate positions instructed bythe control system in the horizontal direction, after sintering of thelayer concerned is completed, at an intermediate height positionaccording to the temporarily stocked coordinate positions instructed bythe control system in the height direction between the position of thesurface on which the sintering has been completed and the lowestposition of a powder supplying blade moving in the horizontal directionfor forming a powder layer on a next layer on the upper side of thelayer concerned, so that the rotating cutting tool cuts any raisedsintered portions, and cutting a periphery thereof according to acutting tool traveling along an outside edge of the periphery to formthe layer of an article, the step of cutting a periphery occurringaccording to one of the following: if the step of causing occurs, beforeor after the step of causing, or if the step of causing does not occur.17. The three-dimensional shaping method according to claim 16, whereinthe width is 2 mm.
 18. A three-dimensional shaping method comprising thesteps of: after formation of a powder layer with a predeterminedthickness, sintering the powder layer by an optical beam and repeatingthe formation and the sintering a predetermined number of times and,wherein the sintering and formation includes the following steps as toeach layer: on an individual layer to be sintered, for detecting alikelihood that raised sintered portions will be present after sinteringfrom a fine sintered region, determining by a control system an undercutangle formed between the upper face and the lower inclined face at theedge of an expected sintered part before sintering the region, and whenthe undercut angle formed between the upper face and the lower inclinedface at the edge of an expected sintered part is greater than apredetermined extent, the region is sintered, when the undercut angleformed between the upper face and the lower inclined face at the edge ofan expected sintered part is determined to be equal to or less than thepredetermined extent, temporarily stocking coordinate positions in ahorizontal direction and a height direction at a region of the shapingpath by the control system, whose undercut angle formed between theupper face and the lower inclined face at the edge of the expectedsintered part has been determined to be equal to or less than thepredetermined extent, sintering the divided block after temporarilystocking, causing the rotating cutting tool to travel around the regionat the temporarily stocked coordinate positions instructed by thecontrol system in the horizontal direction, after sintering of the layerconcerned is completed, at an intermediate height position according tothe temporarily stocked coordinate positions instructed by the controlsystem in the height direction between the position of the surface onwhich the sintering has been completed and the lowest position of apowder supplying blade moving in the horizontal direction for forming apowder layer on a next layer on the upper side of the layer concerned,so that the rotating cutting tool cuts any raised sintered portions, andcutting a periphery thereof according to a cutting tool traveling alongan outside edge of the periphery to form the layer of an article, thestep of cutting a periphery occurring according to one of the following:if the step of causing occurs, before or after the step of causing, orif the step of causing does not occur.
 19. The three-dimensional shapingmethod according to claim 18, wherein the angle is 45 degrees.